A gas turbine engine may be used to power various types of vehicles and systems. A particular type of gas turbine engine that may be used to power aircraft is a turbofan gas turbine engine. A turbofan gas turbine engine may include, for example, five major sections: a fan section, a compressor section, a combustor section, a turbine section, and an exhaust section. The fan section is positioned at the front or inlet section of the engine and includes a fan that induces air from the surrounding environment into the engine and accelerates a fraction of this air toward the compressor section. The remaining fraction of air induced into the fan section is accelerated into and through a bypass plenum and out the exhaust section.
The compressor section raises the pressure of the air received from the fan section to a relatively high level. The compressed air from the compressor section then enters the combustor section, where one or more fuel nozzles injects fuel into the compressed air. The fuel-air mixture is ignited in the combustor section to generate combustion gases. The high-energy combustion gases from the combustor section then flow into and through the turbine section, thereby causing rotationally mounted turbine blades to rotate and generate energy. The air exiting the turbine section is exhausted from the engine via the exhaust section.
Due to the high temperatures in many gas turbine engine applications, it is desirable to regulate the operating temperature of certain engine components, particularly those within the mainstream hot gas flow path in order to prevent overheating and potential mechanical issues attributable thereto. As such, it is desirable to cool the combustor components, such as the combustor liners, to prevent or reduce adverse impact and extend useful life. Mechanisms for cooling the combustor liners include effusion cooling techniques. Effusion cooling involves a matrix of relatively small diameter effusion cooling holes extending through the combustor liners to admit a flow of cooling compressor discharge air. The combustor has an “inside” surface exposed to combustion gases and an “outside” surface exposed to compressor discharge air. The effusion cooling holes are typically angled relative to a surface of the combustor to generate a cooling film on the inside wall of the liner as a buffer from combustion gases. However, given the high temperature of engine operation, cooling remains a challenge. As an example, the small diameter effusion cooling holes may be susceptible to plugging by particles within the engine air flow.
Accordingly, it is desirable to provide combustors with improved effusion cooling arrangements. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.